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Non-surjective coarse version of the Banach-Stone theorem - MaRDI portal

Non-surjective coarse version of the Banach-Stone theorem (Q781706)

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scientific article; zbMATH DE number 7222416
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Non-surjective coarse version of the Banach-Stone theorem
scientific article; zbMATH DE number 7222416

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    Non-surjective coarse version of the Banach-Stone theorem (English)
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    17 July 2020
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    Let \(X\) and \(Y\) be compact Hausdorff spaces and denote by \(C(X)\) and \(C(Y)\) the spaces of all real-valued continuous functions on \(X\), respectively \(Y\), equipped with the supremum norm. The classical Banach-Stone theorem states that, if \(C(X)\) and \(C(Y)\) are linearly isometric, then \(X\) and \(Y\) are homeomorphic.\par Given \(M\geq 1\) and \(\varepsilon\geq 0\), a map \(F:C(X) \rightarrow C(Y)\) is called a coarse \((M,\varepsilon)\)-quasi isometry if \[ M^{-1}\|f-g\|-\varepsilon\leq\|F(f)-F(g)\|\leq M\|f-g\|+\varepsilon \] holds for all \(f,g\in C(X)\). The author proves a version of the Banach-Stone theorem for coarse \((M,\varepsilon)\)-quasi isometries with \(F(0)=0\) and \(M<\sqrt{8/7}\) under a certain approximation condition.
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    Banach-Stone theorem
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    coarse quasi-isometries
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